servo: Merge #17837 - style: Avoid looking at descendant hints to check whether the element needs a restyle (from emilio:assert-fix); r=hiikezoe

This makes us hit some assertions in Gecko.

Source-Repo: https://github.com/servo/servo
Source-Revision: 9f412caab21ae407173187cdb5d0250fb1ae6b37

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : ae0e07a5ec6e096ffed718463f616fcbf03ef913

servo/components/style/data.rs

@@ -324,7 +324,7 @@ impl ElementData {
         }
 
         debug_assert!(hint.has_recascade_self(),
-                      "We definitely need to do something!");
+                      "We definitely need to do something: {:?}!", hint);
         return RestyleKind::CascadeOnly;
     }
 

servo/components/style/dom.rs

@@ -492,7 +492,7 @@ pub trait TElement : Eq + PartialEq + Debug + Hash + Sized + Copy + Clone +
             return false;
         }
 
-        data.has_styles() && !data.restyle.hint.has_non_animation_hint()
+        data.has_styles() && !data.restyle.hint.has_non_animation_invalidations()
     }
 
     /// Flags an element and its ancestors with a given `DescendantsBit`.

servo/components/style/invalidation/element/restyle_hints.rs

@@ -65,8 +65,12 @@ impl RestyleHint {
     }
 
     /// Returns whether we need to restyle this element.
-    pub fn has_self_invalidations(&self) -> bool {
-        self.intersects(RESTYLE_SELF | RECASCADE_SELF | Self::replacements())
+    pub fn has_non_animation_invalidations(&self) -> bool {
+        self.intersects(
+            RESTYLE_SELF |
+            RECASCADE_SELF |
+            (Self::replacements() & !Self::for_animations())
+        )
     }
 
     /// Propagates this restyle hint to a child element.